/*
* Copyright (c) 2008, German Buela
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*     * Redistributions of source code must retain the above copyright
*       notice, this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright
*       notice, this list of conditions and the following disclaimer in the
*       documentation and/or other materials provided with the distribution.
*     * The name of German Buela may not be used to endorse or promote products
*       derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY GERMAN BUELA "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL GERMAN BUELA BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package org.gbuela.avant.http;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStream;
import org.gbuela.avant.Response;
import org.gbuela.avant.ResponseWriter;

/**
 * ResponseWriter implementation for downloading an existing file to the client.
 * @author gbuela
 */
public class FileResponseWriter implements ResponseWriter
{
    private File file;
    private String targetName;
    private String contentType;
    
    /** Creates a new instance of FileResponseWriter */
    public FileResponseWriter(File file, String targetName, String contentType)
    {
        if(file == null) throw new IllegalArgumentException("file must not be null");
        if(targetName == null) throw new IllegalArgumentException("targetName must not be null");
        if(contentType == null) throw new IllegalArgumentException("contentType must not be null");
        if(!file.exists()) throw new IllegalStateException("file doesn't exist");
        
        this.file = file;
        this.targetName = targetName;
        this.contentType = contentType;
    }

    public void write(Response response)
    {
        response.setContentType(this.contentType);
        response.setHeader("Content-disposition", "attachment; filename=\"" + targetName + "\"");
        try
        {
            OutputStream output = response.getOutputStream();
            FileReader fr = new FileReader(file);
            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
            int b = bis.read();
            while(b != -1)
            {
                output.write(b);
                b = bis.read();
            }
            response.flushBuffer();
        }
        catch(IOException e)
        {
            throw new RuntimeException("Error writing response from file");
        }
    }
    
}
